B.1. Core Attributes Prior to HTML 4.0, few attributes could be used consistently for all the HTML tags. HTML 4.0 changed this, defining a set of 16 core attributes that you can apply to almost all the elements in both HTML 4.01 and XHTML 1.0. For brevity, we list these core attributes in this section and spare you the redundancies in the table that follows : class= name | Specify a style class controlling the appearance of the tag's contents. | dir= dir | Specify the rendering direction for texteither left to right ( ltr ) or right to left ( rtl ). | id= name | Define a reference name for the tag that is unique in the document. | lang= language | Specify the human language for the tag's contents with an International Organization for Standardization (ISO) 639 standard two-character name and optional dialect subcode. | onclick= applet | Specify an applet to be executed when the user clicks the mouse on the tag's content display area. | ondblclick = applet | Specify an applet to be executed when the user double-clicks the mouse button on the tag's content display area. | onkeydown= applet | Specify an applet to be executed when the user presses down on a key while the tag's contents have input focus. | onkeypress= applet | Specify an applet to be executed when the user presses and releases a key while the tag's contents have focus. | onkeyup= applet | Specify an applet to be executed when the user releases a pressed key while the tag's contents have focus. | onmousedown= applet | Specify an applet to be executed when the user presses down on the mouse button while pointing to the tag's content display area. | onmousemove= applet | Specify an applet to be executed when the user moves the mouse in the tag's content display area. | onmouseout = applet | Specify an applet to be executed when the user moves the mouse off the tag's content display area. | onmouseover = applet | Specify an applet to be executed when the user moves the mouse into the tag's content display area. | onmouseup= applet | Specify an applet to be executed when the user releases the mouse button while in the tag's content display area. | style= style | Specify an inline style for the tag. | title= string | Specify a title for the tag. | Only a small handful of tags accept none or only some, but not all, of these attributes. They are: <applet> | <base> | <basefont> | <bdo> | <br> | <comment> | <embed> | <font> | <frame> | <frameset> | <head> | <hr> | <html> | <iframe> | <isindex> | <keygen> | <marquee> | <meta> | <nextid> | <nobr> | <noembed> | <param> | <script> | <server> | <spacer> | <style> | <title> | <wbr> | | | For convenience, we've marked each of these tags with an asterisk (*) in the following table, and we list all of the attributes supported by these special tags, including the common ones. For all other tags (those without an asterisk), assume that the common attributes listed previously apply. Do note, however, that the popular browsers do not support all of the HTML 4.0 standard attributes, common or not. Please refer to the main text for details. |